1. Field of the Invention
The present invention relates to a semiconductor manufacturing system with a self-diagnosing function and a self-diagnosing method thereof, and more particularly to a semiconductor manufacturing system with a self-diagnosing function and a self-diagnosing method thereof, for inspecting the positioning accuracy, mechanical accuracy, rotational accuracy and the like of a semiconductor manufacturing system such as a dicing machine.
2. Description of the Related Art
There are many semiconductor manufacturing systems which have a moving mechanism for three axes including X, Y and Z axes and rotary mechanism, etc. turning about these axes. For example, when a wafer is aligned by a dicing machine, a wafer table mounted thereon with wafer is moved in directions of X and Y axes and the wafer table is rotated about its center, so that the wafer can be aligned.
In recent years, miniaturization of a semiconductor chips is planned, and there is required a semiconductor manufacturing system of high accuracy for manufacturing thus miniaturized semiconductor chip. However, even the semiconductor manufacturing system, which has been originally manufactured with high accuracy, deteriorates in the accuracy thereof due to the mechanical wear, slight loosing of screws and and the like as the working time is lengthened. Accordingly, it is necessary that the semiconductor manufacturing system is inspected in each predetermined working time, and, for inspecting the accuracy, a reference wafer for inspecting the accuracy is used for example. On the surface of the reference wafer for inspecting the accuracy, there are formed patterns for inspecting at regular intervals. When this reference wafer for inspecting the accuracy is used in a dicing machine for example, the reference wafer for inspecting the accuracy is moved in directions of X and Y axes to detect the regular patterns, and the thus detected value is compared with an interval between patterns for inspecting the accuracy to thereby inspect the accuracy of the dicing machine.
In the standard wafer for inspecting the accuracy, the patterns for inspecting are formed at regular intervals. Hence, the accuracy of the dicing machine at the time of moving by a predetermined interval can be inspected, however, the accuracy of the dicing machine at the time of moving by a random interval can not be inspected. However, when a wafer is worked on by the dicing machine actually, the dicing machine is moved by a random interval. Accordingly, even if the accuracy of the dicing machine is inspected at the time of moving by a predetermined interval by the conventional reference wafer for inspecting the accuracy, it does not mean that the working accuracy of the dicing machine actually operated is inspected.
That is, with the conventional reference wafer for inspecting the accuracy, the accuracy of the dicing machine deteriorates due to wear of mechanical parts, slight loosing of screws and the like cannot be inspected. Accordingly, until such a state is brought about that the accuracy of the dicing machine is greatly deteriorated the products to be worked on do not satisfy the regulated accuracy, an operator does not notice the deterioration of the accuracy of the dicing machine. However, even when the operator does not notice the deterioration of the accuracy of the dicing machine by the conventional inspection, actually the accuracy of the dicing machine has deteriorated. Hence, the products worked on by the dicing machine during this time do not meet the quality standards. Furthermore, if the maintenance is postponed until the accuracy has become greatly deteriorated, the wear of the mechanical parts, loosening of screws and the like are increased. Hence, a large amount of expense is required for restoration of the accuracy of the dicing machine, and such a problem increases the amount of time required for maintenance.